Manual and semi-automatic telephone system.



w. AITKEN. MANUAL AND SEMI-AUTOMATIC TELEPHONE SYSTEM. APPLICATION FILEDAUG.24. I915 1,21%389. Patented Janj2, 1917.

5 SHEETS-SHEET I- W. AITKEN.

MANUAL AND SEMI-AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED AUG.24, m5.

1,210,389. Patented Jan. 2, 191:.

5 SHEETS-=SHEET 2- 'ru: Menus Ps-rzns co., wnsnmc'rcn. n. c

W. AITKEN.

MANUAL AND SEMI-AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED AUG. 24. 1915.

5 SHEETSSHEET 3- -QWIEHHI W. AITKEN.

MANUAL AND SEMI-AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED AUG-24. I915.

Patented Jan. 2, 1917.

5 SHEETS-SHEET 4.

W. AITKEN.

MANUAL AND SEMI-AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED AUG.24| 1915. 1,210,39.

-SHEET 5- 5 SHEETS Patented J an. 2, 1917.

. TTNT TAT AT WILLIAM AITKEN, OF LONDON, ENGLAND, ASSIGNOB TO THE RELAYAUTQMATIC TELEPHONE COMPANY, LIMITED, OF LONDON, ENGLAND.

Specification of Letters Patent.

Patented Jan. 2, 1917.

Application filed August 24, 1915. Serial No. 47,115.

To all whom it may concern:

Be it known that I, VVILUTAM AITKEN, a subject of the King of GreatBritain, residing at Marconi House, Strand, London, England, haveinvented new and useful Improvements in Manual and Semi-AutomaticTelephone Systems, of which the following is a specification.

This invention relates to telephone sys- 1 terms in which the operationsare wholly or i twenty-eight lines, conforming to the carrying capacityof an order wire and to the ability of the operator to deal with thetrafiic carried by such group. It is, however, recognized that bydividing a number of lines'required for carrying a certain 'trafiic intosub-groups which are served separately, the total number of such linesis increased owing to the fact that the trafiic variations are greaterin small groups than in larger ones. The use of order wires and thesubdivisions thereby required of the junctions into small groupsconsequently reduces the traffic carrying capacity of the junctions.

' Another disadvantage due to the arbitrary division by order wires isthat the incoming calls are spread over a considerable number ofoperators positions and cannot be conveniently concentrated forefiicient operating during slack periods.

Attempts to dispense with order wires have already been made, and onesuch method is to treat the junctions as one group and to fit a lamp atthe A or originating exchange in connection with the jack of eachjunction, such lamp being caused to glow at each position toindicatethatits associated junction is busy. The lamps of busy junctionsthen glow during the whole period of a conversation, and the idle linesare those at which no lamp is glowing. Owing, how ever, to the glare ofthe lamps, to the amount of current used and to the difliculty ofkeeping the A jack marked as busy until the B plug has been withdrawn,this arrangement has not found favor.

In semi-automatic systems various electro-mechanical devices have beenprovided to indicate idle lines by glowing lamps, but these arecomplicated and expensive. I therefore prefer to use lamps, but in orderto overcome the disadvantages just mentioned, I divide thev total numberof junctions between two exchanges into two main groups; one group,usually the smaller, may be called the common or second choice group.The other or larger group is sub-divided into smaller groups, which maybe called the individual or first choice groups. The outgoing junctionmultiple is also divided into sections of ten or other suitable numberof positions and to each section is allotted one individual or firstchoice group of junctions which may be multipled in front of every twooperators positions in such section. The first choice group consists ofsufficient junctions to carry the normal load of the section with whichit is associated. The common or second choice group is multipled (as isusual) in front of every two operators positions over the whole outgoingjunction multiple and consists of suiiicient junctions to carry anytraffic above the normal in all the sections. The total traffic carryingcapacity of the junctions grouped in this way is practically equal tothat of an undivided group adapted for the same traffic.

The result of such a grouping with regard to the aim of this inventionis that the number of junctions at each operators position isconsiderably reduced without afi'ecting the traflic carrying capacity ofthe junctions. Consequently, also, the number of lamps in front of anoperator is reduced in comparison with the known systems mentionedabove, having all junctions multipled over all positions. I havethereby, to a considerable extent, got over the disadvantage due to thecontinuous glare of a large number of lamps and the large amount ofcurrent used. My invention, however, goes farther and has for its objectthe provision of lamp indication entirely without the inconvenience ofcontinuously glowing lamps. For that purpose I arrange the lamps independence on keys in such a manner thatthe lamps glow only when anassociated key is depressed. Such keys may glow lamps in front of one,two or more operators, as desired. The lamps may also be less in numberthan the junctionsof a position, means being then provided forconnecting the lamps with any desired group of junctions.

In addition to a convenient lamp indication and owing to the absence oforder wires, my invention also involves the advantage that the junctionlines may be dis tributed among the B operators in any order and fromany of the A positions as best suits the traffic requirements. Insteadof beingdirectly associated with plugs at the B positions, the junctionlines may end in automatic, distributing mechanisms which will connect aline to a plug in frontof any idle B operator or connect two operatorsin rotation or the like.

The manner in which the invention is'to be carried out will now bedescribed with reference to the diagrams in which:

Figure 1 shows a method of grouping junctions bet veen an exchange A andan exchange 13. Fig. 2 shows one method of indicating engaged junctionsto an A operator. Fig. 3 shows an alternative method of indicatingengaged junctions to an A opera- 7 tor. Fig. 4: shows such indicatingmeans in conjunction with a cord circuit at the 13 exchange and themethod of maintaining a junction busy until the plug is withdrawn at theB exchange. Fig. 5 shows an arrangement of circuits wherebythe cordcircuit at the B exchange is severed when an. A operator takes down theconnection.

Fig. 1. Taking for example two exchanges between which there are onehundred junctions and at one ofwhich, the A exchange, there are fiftyoperators positions. These are divided into five sections, R, S, T, U,V, each of ten'positions. The one hundred junctions are divided into twogroups, one of, say, seventy-five, and the other of twenty-five. Theseventy-five junctions are further sub-divided into five first choicegroups, M N O P Q of, say, fifteen 7 each; that is one to each section,B S T U V of the switchboard, and the group of junctions may be, as inpresent practice, multipled at each two positions of its particularsection. Only three lines are shown in each of the groups M, N, &c., butit is to'be understood that there are fifteen in each group.

The remaining twenty-five junctions L are multipled at eachtwo-positions throughout the whole length of the outgoing multiplethatperiod will the common or second choice wire key at present used.

group L be used, and only by the operators one group as regards carryingcapacity.

Fig. 2 shows a lamp in connection with the jack of each. outgoingjunction; each operator in the exchange is provided with a keycorrespondin somewhat to the order 7 The lamp test may be continuous allaround the board, or it may be divided into sections which may or maynot correspond to the sections R S T U V, Fig. 1. Common toa'section isrelay a. which on the depression of any key in the section is energizedand connects ,the third or test wire of eachof the jacks j in thesection to the coil of an individual re- 7 lay b. In the jack of anyjunction ,which is engaged there will be a plug .32 on the thirdconductor of which there will be negative potential. Consequently, onan'operator pressing a key is to test, all the relays 'b of engagedjunctions will operate and negative battery will be connected to thelamps Z associated therewith which will therefore glow. Preferablythe'keys of the relay a are slow to release so that even though anoperator remove her finger from the key before inserting a plug into anidle junction she will nevertheless be notified by the subsequentglowing of the lamp if another operator has taken the junction 'she wasabout to use. r

Fig. '3. To reduce the number of lamps and consequently the height ofthe junction multiple, the number of busy-indicating lamps may be lessthan the numberof jacks, for example, one strip of lamps may be providedfor four exchanges G H J K. Thus, if an operator wishes to test an idlejunc- Under such conditions the groups 7 are equal to a similar numberof lines in tion to G she will press key 9 which will i energize lefthand relay a: to connect the third wires of the G junction to the testerrelays b and consequently the lamps Z associated with engagedGrjunctions willglow. The test-lamps in such an arrangement mustbeindividual to each operators position/ As there must be, some timeinterval be tween the glowing of the clearing lamp at the 13 positionand the withdrawal of the. plug p from the jack at the termination of.the conversation and after the operator at exchange A has taken down herpart of the connection, it is necessary to provide some means whereby ajunction tests engaged until the plug is withdrawn at exchange B. Thisis accomplished by providing the tester relays as shown in Fig. A withtwo coil windings one of which is connected via springs of relay a tothe third wire of the associated junction, and the other via springs ofa. and via springs on a cut-off relay 0 to one of the line conductors.

The following is a description of the operation in which a key 70, forinstance, is depressed and a common relay a energizes over circuit 1. Ifthe junction is engaged, relay Z) will be energized by negative from theplug third conductor over circuit 2, and will glow the lamps Z overcircuit 3. The operator will consequently not take that junction. If itis free the lamp will not glow and the operator will plug into the jackto connect negative over circuit 4 through the supervisory lamps d andcut-off relay 0 which operates to insulate the line conductor from thetester. The manner in which the calling lamp 0 is caused to glow isobvious and need not be described. The operator at the B exchange seeinglamp 0 glowing, depresses a speaking key f which connects her telephoneset across the junction circuit and also closes a circuit 5 through aholding magnet i and contacts of release relay m. Consequently key 7will be held down. The operator at exchange B after ascertaining whatconnection is wanted inserts the plug 10 to complete the con nection,and in so doing also completes circuit 6 through release relay m andclearing lamp n. m then energizes to break circuit 5 and to preparecircuit 7. The speaking key 7 is thus restored, and the B operatorstelephone cut out of the junction circuit. At the termination of theconversation, if the operator at exchange A takes down the connectionbut the operator at B delays doing so, and another or the same operatorat A tests for an idle junction, circuit 7 will be completed at relays cand a to the second coil of tester relay 6 which will energize to causelamp Z to glow to indicate that it cannot be used.

Fig. 4 shows also how the tester for the common or second choice groupof junctions mentioned in connection with Fig. l is brought into use ifall the junctions of the individual or first choice group be in use. Ifthis be so, on a key is being depressed, all the relays b will beenergized and circuit 8 completed through common relay a to bring in asecond tester. Each time the second tester is brought into use the factis registered by a meter 9 in circuit 9 and the pilot lamp 1* glows. Ifall the common group junctions are engaged this fact is registered bymeter g. It will be seen that as the second tester is not brought intouse until all the first choice group junctions are engaged the operatorsmust use all idle first choice junctions before they can use secondchoice junctions.

Fig. 5. As delay in operating will be caused by a junction testingengaged until the plug is withdrawn at the exchange B and as, moreover,the out-of-use time of the junction is unnecessarily lengthened thejunction circuit at exchange B may be disconnected from the cord andplug as soon as the operator at exchange A takes down her part of theconnection. The re-connecting of the cord and junction circuits is inthe hands of the operator at B, so that an operator at A may now take upthe junction (even though the plug is in a subscrib ers line jack at B)and the calling lamp will glow. One way in which this is effected is asfollows: A relay S is provided which normally disconnects the cordcircuit from the junction line circuit and the busying potential fromthe plug third connection; also the calling lamp circuit 10 is completed through a back contact on the relay. It is not necessary todescribe again the testing and calling by the operator at A. Theoperator at B seeing lamp a glowing presses speaking key f to connecther telephone set across the junction circuit. Key 7 holds itself andcloses circuit 11 through relay S, which operates and locks circuit 12to connect the junction and cord circuits together, to disconnect e andto prepare 6 through supervisory lamp n. The operator at B havingascertained the desired connection and by testing found that the line isnot engaged inserts plug 39- in the required subscribers line jack.Circuit 6 is therefore completed through relay m which operates and cutscircuit 5. Key 7 is released and circuit 11 through S broken. At thetermination of the conversation the operator at A takes down her part ofthe connection, releasing relay 25 and consequently breaking circuit 12thereby releasing S. The junction and cord circuits are now againdisconnected and although plug 79 may be left in a jack thecorresponding line will not test engaged; furthermore, the supervisorylamp .n will cease to glow, thereby indicating to operator B that shemay take down her connection. If, before she does so, another connectionis made at exchange A to the junction, circuit 10 will be reformedcausing the calling lamp 6 to glow as before.

In the junction cord circuits no key or other apparatus is shown forringing, it being, of course, obvious that either key or keyless ringingmay be employed, also the particular circuits shown are not essential tothe invention, as many modifications may be made to obtain similarresults.

What I claim is- 1. A telephone system comprising a manual switch-boarddivided into sections, a group of outgoing lines allotted to eachsection of the board, a further group of outgoing lines common to aplurality of sections of the board,-a number of lamps, a relayassociated with the test wire of each outgoing line and adapted toconnect up one side of a lamp associated with such line, means forenergizing the relays of busy lines, a key associated with each section,means whereby on the depression of said keys the lamps are glowed onbusy lines of the section group and means whereby lamps in the commongroup are glowed when all the lines of the section group are busy.

2. A telephone system comprising a manual switch-board divided intosections, a group of outgoing lines allotted to each section of theboard, a further group of outgoing lines common to a plurality ofsections of the board, a number of lamps, a relay associated Withthetest wire of each outgoing line and adapted to cut oil a wire from thetalking circuit, a key associated with each section, a switching relayadapted to be energized on the depression of a key, a number of testerrelays, means whereby a tester relay is connected in parallel with eachof the third conductor relays, means for energizing the tester relaysandthird conductor relays of busy lines to glow lamps in the sectiongroup and means whereby lamps in the common group are glowed when allthe lines of the section group are busy.

3. A telephone system comprising 'a manual switch-board divided intosections, a group of outgoing lines allotted to each section of theboard, a further'group of outgoing lines common to a plurality ofsections of the board, a number of lamps, a

relay associated with the testwire of each outgoing line and adapted tocut oil a wire from the talking circuit, a key associated with eachsection, a switching relay adapted to be energized on the depression ofa key,

a number of tester relays, means whereby a tester relay is connected inparallel with each of the third conductor relays, jacks at each end ofthe lines, plugs for said jacks and means for energizing the testerrelays and third conductor relays of busy lines to glow lamps in thesection group and means whereby lamps are glowed on busy lines after aplug has been removed from the outgoing jack of a line and until theplug is 7 Copies of this patent may be obtained for five cents each, byaddressing the Commissioner of Patents, Washington, D. G.

